Need really good takeout meatballs in Brooklyn asap

We are having our daughter's fifth birthday party tomorrow. I had planned on my mom bringing her amazing meatballs for the meal but she isn't coming due to the rain. I am now scrambling to find really good meatballs and sauce. I like them soft and flavorful and not the size of fists. We are in Park Slope but willing to travel a bit I necessary. Any great recs would be greatly appreciated.

I buy them at Meats Supreme all the time when I'm too lazy to make them myself. They are very good as is their homemade sauce which you can buy by the jar. There are 4 locations in Brooklyn, two on 86th Street. You can take the D train to 18th Avenue or Bay Parkway. There is a location near each stop. I believe they are $3.99 per pound and they are in sauce (in the deli department). If they are too big for you (golf ball size) you can cut them in half. They also have smaller meatballs in their meat department (not in sauce). They are pre-packaged and not nearly as good. I think they must buy those from a vendor. I don't know why. You can also buy a zillion types of pasta there and some great breads too.

costco has quite good beef meatballs in their freezer which folks from my church prepare all the time, with a good sauce would be very suitable for your party.. At the other end of the spectrum, Brooklyn Larder has ldeliciousmeatballs too, but not at a price I would recommend for a group!

Brancaccio's meatballs are great but I would not recommend them for a sauce. If I recall they have a touch of sweetness (raisins or currants?) and I think they are best eaten as a dish in themselves. Looking forward to trying Forninos new meatball outpost in the slope!